Wiper blades of windshield wipers comprising a wiper strip unit, said wiper blades having a first wiper lip and a second wiper lip, have already been proposed in the publications DE 1 170 806 B, DE 27 05 700 A1 and DE 43 17 833 A2. Switching between the wiper lips is achieved in this case by frictional contact with a windshield when reversing a movement of a wiper blade.